Filter for domestic appliance



1965 B. L. BRUCKEN ETAL 3,198,333

FILTER FOR DOMESTIC APPLIANCE Filed Jan. 2, 1962 ISheets-Sheet 1INVENTORS Byron L. Bracken l icfor A. William/H's The/r Alrbmey Aug. 3,1965 B. L. BRUCKEN ETAL 3,198,333

FILTER FOR DOMESTIC APPLIANCE Filed Jan. 2. 1962 4 Sheets-Sheet 2 2 12*(l) 0,64 0 (5 r i 4 5e I l l "s2 as I INVENTORS' Byron L. Bracken V/cfarA. William/N's The/r Attorney Aug. 3, 1965 5.. BRUCKEN ETAL 3,198,333

FILTER FOR DOMESTIC APPLIANCE Filed Jan. 2, 1962 4 Sheets-Sheet 3 I m ll20 us INVENTORS Byron L. Bracken By Victor A. William/Ills Fig.

Their Attorney Aug. 3, 1965 B. BRUCKEN ETAL 3,193,333

FILTER FOR DOMESTIC APPLIANCE 4 Sheets-Sheet 4 Filed Jan. 2, 1962INVENTORS Byron L. Bracken BY Victor A. William/71's The/r AttorneyUnited States, Patent 3,198,333 FILTER FOR BUMESTIE APPLIANCE Byron L.Bruciren and Victor A. Wiliiamitis, both of Day= ton, Ghio, assiguors toGeneral Motors (Iorporation, Detroit, Mich, a corporation of DeiawareFiled Lian. 2, 1962, Ser. No. 163,893 3 Claims. (El. ZIlI-Zll?) This isa continuation-impart of our copending application Serial No. 105,670,filed April 26, 1961 now US. Patent No. 3,133,286 (granted May 12,1964).

This invention relates to a domentic appliance and more particularly toan improved replaceable paper filter for a coin operated dry cleaningmachine.

In dry cleaning apparatus, it is desirable to maintain the solvent in asuitably filtered or, uncontaminated condition in order that the clothesare cleaned efiiciently. Where a domestic appliance is adapted for useinterchangeably as a clothes washer or a dry cleaning apparatus, it isdesirable to locate the solvent filter for the dry cleaning apparatus ina readily accessible position.

Accordingly, it is an object of this invention to adapt a clotheswashing machine for dry cleaning.

Another object of this invention is the provision of a solvent filter inthe console of a washing apparatus.

Another obpect of this invention is the provision of a readilyaccessible and disposable filter insert for the console of a drycleaning apparatus.

It is a further object of this invention to provide a dry cleaningapparatus with a filter above the spin tub such that a continuousoverflow of solvent may be effected throughout an agitate period.

A more specific object of this invention is the provision of anelongated accordion-pleated removable support element for a filter sheetin the console of a washing apparatus.

Another object of this invention is the provision of a replaceableaccordion-pleated paper filter cartridge for a liquid dry cleaningsolvent, said paper being impregnated with a lignite carbon complex forsorbing dyes from the solvent.

A more general object of this invention is the provision of formablepaper filter sheeting which has variably diffused throughout its crosssection a surface active agent for absorbing dyes.

Still another general object of this invention is the provision of adisposable filter insert for removing particulate matter from acirculating dry cleaning solvent, said insert having intimately andintegrally retained therein additional solvent treating agents forconditioning the solvent for the dry cleaning process.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein preferred embodiments of the present invention areclearly shown.

In the drawings:

FIGURE 1 is a schematic side sectional view, partly in elevation, of adry cleaning apparatus suitable for use with this invention.

FIGURE 2 is a fragmentary sectional view, partly in elevation, takenalong line 2-2 in FIGURE 3 to show the. removable filter supportarrangement of this invention.

FIGURE 3 is a fragmentary top elevational view of this invention withthe filter container cover removed.

FIGURE 4 is a top elevational view of the dry cleaner of this inventionwith parts broken away.

FIGURE 5 is an enlarged sectional view of the disposable filter and theremovable filter support.

FIGURE 6 is a top elevational view of another embodiment of thisinvention with its cover removed.

ice

FIGURE 7 is a fragmentary sectional view of the filter taken along line7-7 in FIGURE 6 and installed on a dry cleaning apparatus.

FIGURE 8 is a fragmentary side sectional view, partly in elevation, ofthe dry cleaner of FIGURE 1 adapted for use with a third filterembodiment of this invention.

FIGURE 9 is a fragmentary side sectional view, partly in elevation, ofthe filter cartridge in FIGURE 8.

' FIGURE 10 is a top elevational view, with parts broken away, of thefilter cartridge of FIGURE 9.

FIGURE 11 is an enlarged cross sectional View of the filter paper sheetused in the filter cartridge of FIGURE 9.

In accordance with this invention and with reference to FIGURE 1, awashing apparatus 10 is illustrated as adapted for use as a dry cleaner.The washer It] is comprised of an outer casing 12 having a top wall 14and an access opening 16 which is closed by a hinged access lid 13.Within the outer casing I2 is disposed a cyclindrical solvent containerZil which is imperforate except for a top opening 22 and a bottom outlet24 at the lowest point thereof. A central bulkhead 26 serves to supporta spin tub 28 for rotation Within the solvent container. The spin tub 28has a top access opening 30 in axial alignment with the cabinet opening16 and a plurality of circumferentially arranged outflow ports 32.Within the spin tub 28, an agitator 34 is located. Beneath the bulkhead26 and suspended thereby is an agitating and spinning mechanism showngenerally at 36 which is adapted to selectively rotate the spin tub 2%when the mechanism motor 33 is rotating in one direction and tovertically reciprocate the agitator 34 when the motor 38 is reversed.For further details pertaining to the agitator and spinning mechanism36, reference may be had to the Sisson Patent 2,758,685, issued August14, 1956.

Turning now to FIGURES l and 4, the top wall 14 of the casing 12 isshown with a raised rear console support portion it) on which issupported a console filter container or box shown generally as 42. Theconsole filter is comprised of a box-like filter container 44 having atop opening 46 closed by a removable cover 48. The bottom wall 56 or"the filter container is imperforate except for an outlet opening 52which is connected by a supply conduit 54 in overlying relationship withthe top opening 30 of the spin tub.

When the filter container cover 43 is removed, the filter container isadapted to receive a box-like filter support frame 56 comprising a pairof end plates 58 and 60 be tween which extends a serpentine oraccordion-pleated reticulated support form or screen 62. The screenrests at its opposite ends on complementary shoulders 63 fastened as bywelding to each end plate. Each end plate may also include overflowby-pass ports such as 64 and 66 respectively. This provides forbypassing solvent around the filter in case the supply to the filter isgreater than the filter capacity as will be understood more fullyhereinafter. The filter frame 56 is generally rectangular in form and ofsmaller dimension than the filter container 44 such that the filterframe is spaced from the container about its periphery to form aclearance 70 between the filter frame and the container.

In considering a self-contained dry cleaning and solvent purifyingsystem such as set forth for the apparatus 19, it appears that sorptionand filtration can. be an effective and economical manner of maintaininga solvent in an uncontaminated condition. The materials to consider indry cleaning for use in filtration of lint, dirt solids, organic acidand even some of the cleaned off oil and grease are activated carbon,fullers earth, bauxite and similar sorbing clays, treated or untreated,diatomaceous earth, magnesium oxide, silica gel, alumina and molecularsieve. Actually a mixture of these would serve best. Activated charcoalshould be included as the most potent scavenger for any dyes removedfrom clothing. Magnesium oxide would be included as a preferred agentfor sorbing any free fatty acid. The acid clays such as fullers earthwould be economic sorbers of some of the general oil and grease. Thediatornaceous earth would assist in building a free-flowing filter. Acombination or composite of the above elements (FIGURE would be formedinto a suitable filter sheet or ribbon 31] having a porous paper backing82 for retaining in sandwiched relation the filter composite 34. Thus, asheet of the filter 81 as Wide as the upport 56 can be presseddownwardly into coextensive engagement with the support screen 62 on thefilter frame. The sheet of filter paper 80 may be replaced as often asnecessary to provide for effective filtration of the recirculatingsolvent.

Completing the solvent circulating system and with reference to FIGURES1, 2 and 3, a solvent distribution header 86 is illustrated at one endof the filter container 42. The filter header is supplied by way of asupply conduit 88 and includes a plurality of solvent spray ports 96above the top of the filter frame 56. A pump 92 is connected by aconduit 94 to the solvent container 24 and includes a pump outlet 96which is connected to the header supply conduit 88 through a solenoidoperated valve 98 (for retaining the solvent in the solvent storagecontainer 20 when the equipment is not in operation) and a three-wayvalve 100 (for selectively directing the solvent to a Waste drain 1M,the filter chamber 42 or a solvent make-up line 1114).

In operation, clothes are placed through the access opening 16 into thespin tub 28 and the cleaning cycle initiated through any conventionalcoin operated timing mechaism such as 1116. The pump 92 will be operatedby the motor 38 to circulate the solvent from its storage in thecontainer 20 to the spin tub 28 as follows. The valve 93 will be in anopen condition and the solvent will be pumped through the three-wayvalve 101]) to the header supply conduit 83. The solvent will enter thefilter container 44 at the solvent distribution header 86 and will bedistributed substantially equally about the top of the accordion pleatsor folds of the filter 8th. The solvent will flow by gravity through thefilter element 80, returning to the filter container or box 44 along thebottom wall thereof from which point it will drain by gravity throughthe conduit 54 to the spin tub. Should the pump 92 supply solvent to thefilter container 44 faster than it can flow through the filter element 8the level of the solvent will rise until it reaches the bypass ports 64,66. Then the solvent will flow around the filter 80 by overflowing thefilter support 56, thereby going directly to the spin tub 28 withoutfiltration. Periodically, it will be necessary to remove the cover 48 ofthe filter container and strip off the contaminated filter paper. A newstrip of filter paper will be pressed into engagement with the folds ofthe support screen to place the equipment in condition for additionaldry cleaning cycles.

' With reference to FIGURES 6 and 7, a round starshaped cartridge orcanister 11% is illustrated which inserts withina cylindrical filtercontainer 112 positioned on the washer console. As with the preferredversion, the filtered fluid returns by gravity to the spin tub by way ofa conduit 114. More particularly, the filter cartridge 110 is formed bya folded or pleated support screen 116 held together at the top andbottom by a reinforcing strip 111. Filter paper 113 such as used on thepreferred version is adapted to be pressed into engagement with theradially inner side of the screen. The cartridge is carried on agenerally imperforate circular bottom support plate 118 having an inletport 120. Solvent is pumped through a conduit 122 into the center of thefilter cartridge 110 and flows as shown by the arrows radially'outwardlythrough the filter element 113 and the screen 116 into the clearancespace 124 between the 4 filter cartridge and the cylindrical container112. As with the preferred version, a by-pass arrangement is effectedsince the top 126 of the filter cartridge 110 is open to permit asolvent oversupply to overflow the top of the cartridge in passingdirectly to the tub. Here, also, the cartridge 110 is removable so thatthe filter 113 may be stripped from the support screen 116 and replacedwith a fresh filter.

Another aspect of this invention wherein dry cleaning additives arecombined into a replaceable filter cartridge is shown in FIGURES 8, 9,10 and 11. Referring now to FIGURE 8, the dry cleaner 10 includes on theconsole thereof a cylindrical container or housing 141) having a topopening 142 closed by a cover 144. The cover 144 is generallyimperforate and is retained securely on the filter container 141 byclamps 146. The filter container 1% includes an outlet port 148 definedby a raised rib 15% which connects with the supply chute 54 forsupplying filtered and decontaminated or conditioned solvent to the spintub or cleaner basket 23. Contaminated solvent is returned through thesupply conduit 88 to an inlet opening 152 in the bottom of the filtercontainer 144 The removable and disposable filter element 154 isinsertible through the opening 142 in the filter container. The filter154 is comprised of a metallic generally circular top plate or support156 and a metallic bottom circular plate or support 158 spaced from theupper plate by a perforated cylinder 160 of metal, hardboard or othersuitable material. A ring-like bail or handle 162 is welded as at 165 tothe top plate 156 and half thereof may be bent away from the surface ofthe plate in order to provide a handle for removing the filter cartridge154. Each plate 156 and 158 is formed with an up-turned annular flange164 and 166 and a radially inner rib 168 and 170 for nestingtherebetween an annulus of folded or accordion-pleated filter paper 172.

The accordion-pleated filter paper is formed with radially inner folds174 touching the outside of the perforated cylinder 160 while the outeredge of the folds 176 it: retained within the peripheral edge flange 164and 166 the oppositely facing end plates 156 and 158. A bed ofthixotropic epoxy cement or other suitable adhesive is formed withinvthe annular channel 178 and 180 on each of the end plates to retain theends of the filter pleats in sealing engagement.

To form the accordion pleats, a strip of filter paper as wide as thefilter cartridge is tail is formed into a series of consecutive pleatsor folds having a depth equal to approximately A the diameter of thefilter cartridge. The folded sheet of filter paper is then formed intoan annulus or cylinder in a manner to place the terminal portions orsheet ends 184 and 186 in juxtaposition. These terminal portions areinterlocked and a plurality of staples 188 positioned in spacedrelationship along the length of the fold to hold the filter paper inproper relation to the end plate and to provide a seal along the joinededges. The proportions of the fold to the overall diameter of the filtercartridge are determined at A of the diameter in order to realize amaximum paper surface area available for effective filtering. Forinstance, where the cartridge 154 is 14% inches in length and 7 inchesin diameter, one hundred and forty quarter-diameter folds of filterpaper are necessary to provide approximately fifty square feet of filtersurface in the cartridge. This filter paper surface area has beendetermined as sufiicient to process adequately a six gallon per minutesolvent flow through the filter cartridge.

The bottom plate 158 in the filter cartridge has an inturned collar 190to form a filter outlet and a rib 192 which mates with the filtercontainer rib 148 to form a metal to metal seal between the filtercontainer and the filter cartridge. For simplicity in manufacture, theopposite end plate 156 is also formed with a collar 194 so that only oneend plate die is necessary. The cover 144 includes a cen- {3 J3 tralrecess which nests in sealing engagement with the collar 194 so that thesolvent flow is from the radially outer side of the filter cartridgethrough the folds of the filter paper to the perforated cylinder 160.From this point the filtered and decontaminated or treated solvent fiowsby way of the outlet port 190 in the bottom end plate 158 to the supplychute 154 leading to the spin tub.

In the first mentioned embodiments of this invention, the variousadditives necessary for treating dry cleaning solvent are heldphysically between spaced laminations of filter paper (FIGURE 5). Inthis arrangement, the spacing of the paper laminaticns is important forretaining the composite of dry cleaning solvent treating agents withinthe filter sheet at a consistent thickness and with the agents properlyproportioned. On the other hand, in the embodiment of FIGURE 11, theactivated carbon or charcoal particles are actually held mechanically byand interspersed between the multitude of fibers in the paper. Thus, theconstruction of the filter sheet is reduced to the ultimate insimplicity.

The cross section of the filter paper 172 is shown in FIGURE 11 toinclude the solvent treating agent particles 200, such as activatedcarbon, and the paper fibers 202, such as cotton linters or the like.Note that the fiber 202 are generally more dense near each surface 204and 206 of the filter sheet, whereas the treating agent particles 200are most concentrated in the center of the sheet. In other words, therelative amount of fibers to carbon particles is very great at the papersurface; whereas, centrally, the fiber-carbon particle ratio changesmore nearly to that ratio of the total mixture proportions, as will beunderstood more fully hereinafter. Such construction forms a ratherdiffused and dispersed lamina which keeps the treating agent generallyremote from the surface of the filter sheet and facilitates cleanlinessin handling the filter paper. Further, Where a surface active agent oradsorber such as activated carbon is used, the more that the carbonparticles 200 are dispersed, the more will be the exposed reactingsurface of the particle. There is also less tendency for the carbon todust off of the filter paper and, therefore, there is a minimum loss ofcarbon. Still further, such particle dispersal makes the paper morepliable and therefore more processible into folds for the filtercartridge. Since less carbon is required in a given sized filtercartridge with the dispersed form, filter cartridge cost is held to aminimum. The reason that the carbon particles are so efilciently used issimply that the particles are in fine or powdered form and so completelydispersed and suspended by the paper fibers that the maximum carbonparticle surface is exposed to sorb dyes from solvent moving through thefilter paper.

One method of making the filter paper 172 is as follows. Using thewell-known Fourdrinier paper making process, a homogeneous suspension orslurry of paper.

pulp, in water, is fed from the heaters to the endless screen beltportion of the Fourdrinier machinery. A short distance downstream fromthe introduction of this paper pulp slurry and shortly after the paperfibers start to settle, a

water-carbon slurry is introduced uniformly at or over the surface ofthe pulp slurry while the paper fibers are still settling into a mat onthe moving and laterally vibrating screen. Paper fibers settle from thepulp slurry both above and below the carbon. Thus, a paper mat continuesto build up as the fibers and carbon settle and a filter sheet is formedwhich, when evacuated of moisture and dried, provides the structureshown in FIGURE 11.

Continuing the disclosure of the filter sheet structure of FIGURE 11,assume for purposes of clarity that 204 is in the bottom surface ofpaper forming by the Fourdrinier process and that 206 is the top surfacethereof. The dense fiber layer (relatively little carbon) at the surface204 is due to the advance settling of paper fibers from the pulp slurrywhich initiates the formation of the paper mat before the carbonparticle slurry is introduced. A rather thin skin of intertwining fibersis thereby adapted to receive the first settlings of carbon particlesfrom the mixture of pulp slurry and carbon slurry above. Since thecarbon particles are heavier than the paper fibers, the carbon willsettle more quickly onto the initial paper mat formation and a densecarbon layer (relatively little fibers) next forms as the result of thevariable settling rates of'carbon and fiber. Lastly, and after most ofthe carbon particles have settled into the center layer or laminate, thefilter sheet is completed as the settling process concludes with a densefiber layer (relatively little carbon) forming the top surface 206.Thus, as evidenced by the somewhat ex aggerated representation of FIGURE11, a generally laminate filter sheet results (fiber-carbon-fiber), butwherein lesser amounts of carbon are dispersed throughout the outerfiber skins while lesser amounts of fiber permeate the center of thepaper for retaining and spacedly supporting the predominant carbonparticles for maximum surface exposure to sorb dyes from the solventbeing filtered. Other granular solvent treating agents could be formedinto filter paper in essentially the same manner.

By way of example, but not by way of limitation, the solvent treatingagent 200 used with the filter paper may be a powdered Darco Blue Labelactivated carbon available from the Darco Chemicals, Division of theAtlas Powder Company. The sieve analysis of the powdered carbon underthe US. Standard Sieve Rating is as follows:

Percent (A) Retained on 100 mesh (0.0040 inch) 1.58 (B) Retained on 140mesh (0.0041 inch) 12.20 (C) Retained on 170 mesh (0.0035 inch) H 41.10(D) Retained on 200 mesh (0.0029 inch) I- 5.24 (E) Retained on 230 mesh(0.0024 inch) 19.30 (F) Retained on 325 mesh (0.0017 inch) 14.10 (G)Through 325 mesh 0.40

(H) 6% was held up in the sieve screens.

The foregoing analysis of carbon was introduced separately as a waterslurry of carbon to the screen belt of the Fourdrinier machine after thepulp had already been placed on the screen. The side shake of the screenpro vided essentially a laminate of fibers-carbon-fibers with a carbonretention of to 99% by weight. The above sieve analysis carbon waschosen as most suitable for dispersal in the additive-type filter paperof this invention. Substantially larger carbon particles would make thepaper too open and therefore not a good filter. Substantially smallercarbon particles would tend to plug the pores of the paper and wouldtherefore prevent high speed filtration.

The fibrous material 202 in FIGURE 11 may be either cotton linters orcellulose fibers combined with a highly hydrating substance such as DuPont HS1 fibril-the latter serving to shrink, when dry, into lockingengagement with the fibrous material and, thereby, enhance the tensilestrength and stiffness of the filter paper.

The filter paper 172 used on the filter cartridge 154 has preferredfilter making characteristics, when its original base Weight, includingthe retained carbon particles, is 140 pounds per 3000 square feet offilter paper. The slurry of paper pulp, without carbon, includes, byweight, approximately to of paper fibers (cotton linters or cellulosefibers) plus 5% to 15% of HS1 fibril. Carbon, weighing approximately 50%of the base weight of paper fibers and fibril, is then added to theslurry. The filter paper has an Air rating of 8 millimeters of waterpressure. The Air is the pump pull, in millimeters of water pressure,that it takes to flow 85 liters per minute through a hundred squarecentimeter circle of the filter paper; thus, the higher the Air rating,the more dense the paper.

In summary, filter paper made in accordance with the teachings of thisinvention and weighing pounds per 3000 square feet preferentiallyincludes 70 to 75 pounds of paper fibers and approximately an equalquantity of Darco Blue Label activated charcoal. More particularly,

carbons made from lignite are preferred in the manufacture of the filterpaper of this invention.

In the manufacture of the filter paper, resin coated fibers are usefulin conjunction with the surface active materials, however, no resincoating on the charcoal carbon or sweetner can be tolerated. This isaccomplished by utilizing a water soluble phenolic resin added to thebeater on the Fourdrinier machine which coats the cotton linters orfibers before the carbon is introduced to the mat, thereby effecting anuncoated carbon particle. Whether coated or uncoated paper fibers areused, the pore size of the paper-additive composite desired should be anominal 20 to 25 microns with a useful range of from 1 to 35 microns ofopening size. This dimension is of practical significance to the size ofparticles which can pass through the filter paper used on theaccordionpleated element 154.

Although the foregoing has disclosed one method of making a solventfilter paper carrying a diffusion or dispersion of activated carbonparticles therein, it should be recognized that other dry cleaningadditives or solvent treating agents such as mentioned earlier in thisspecification could be used and dispersed in the same manner throughoutthe filter sheet construction shown in FIG- URE 11.

it should now be seen that an improved dry cleaning apparatus has beendevised wherein a pro-built filter element is self-contained and readilyaccessible for easy replacement.

While the embodiments of the present invention as herein disclosedconstitute preferred forms, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. A dry cleaning solvent filter for removing particulate matter andtreating a liquid dry cleaning solvent and comprising a filter containerhaving a container adapted to receive solvent returning from a drycleaning apparatus and a container outlet adapted to supply said drycleaning apparatus with filtered and treated solvent, said containerhaving an opening and a cover for closing said opening, and a filtercartridge insertible through said opening, said cartridge including abottom plate having a filter outlet port, a top plate effectivelyimperforate and in spaced parallel relationship to said bottom plate, aperforated cylinder perpendicular to said plates and extendingtherebetween with one end thereof in communication with said filteroutlet port and a longitudinally extending accordion-pleated annulus offilter paper sheeting interposed in sandwiched relationship between saidplates, said accordion-pleated annulus having a creased radially innerfold engaging said perforated cylinder and a creased radially outer foldextending substantially to the periphery of said plates, said foldsforming a partition having an inside wall in communication with saidfilter outlet port through the perforations of said cylinder and anoutside wall in communication with said container inlet, said filterpaper sheeting comprising an integral filtering mat of interwoven paperfibers throughout for removing particulate matter from said solvent anda particulate surface active agent, the particles of which are variablydispersed throughout said mat from one outer surface thereof to theother outer surface thereof for treating said solvent, said paper fibersbeing more dense near each surface of said filter paper sheeting, andthe particles of said surface active agent being more dense in thecenter of said filter paper sheeting remote from the surfaces tofacilitate the retention of said particles in said filter paper sheetingwhen said sheeting is folded.

2. A dry cleaning solvent filter materials for liquids defined by aunitary sheet including depth filter means comprising an integralfiltering mat of interwoven fibers throughout for removing particulatematter from said liquids, and liquid conditioning means for treatingsaid liquids, said liquid conditioning means comprising particles beingheld by said depth filter means in dispersed relationship throughoutsaid unitary sheet from one outer surface thereof to the other outersurface thereof, the fibers of said depth filter means being more densenear each surface of said sheet, and said liquid conditioning meansbeing more dense in the center of said sheet remote from the surfacesthereof to facilitate the retention of said liquid conditioning means insaid sheet.

3. A dry cleaning solvent filter for removing particulate matter andtreating a liquid solvent and comprising a filter container having acontainer inlet adapted to receive contaminated solvent and a containeroutlet adapted to supply filtered and treated solvent, said containerhaving an opening and a cover for closing said opening, and a filtermember insertible and removable through said opening, said filter memberincluding a support and a filter paper portion carried by said support,said filter paper portion forming a partition having one side incommunication with said container outlet and another side incommunication with said container inlet, said filter paper portiondefined by a unitary filtering sheet comprised of interwoven cottonlinters throughout for removing particulate matter from said solvent andactivated carbon particles interposed among said linters from one outersurface of said filtering sheet to the other outer surface thereof andpositioned thereby for treating said solvent, said cotton linters beingmore dense near each surface of said filtering sheet, and said carbonparticles being more dense in the center of said filtering sheet remotefrom the surface thereof to facilitate the retention of said carbonparticles in said filtering sheet.

References Cited by the Examiner UNITED STATES PATENTS 2,218,800 10/40Williams 210-438 2,343,437 3/44 Wells 210-502 X 2,413,954 1/47 Conterman21045l 2,708,982 5/55 McGuff 210505 X 2,796,989 6/57 Kovacs. 3,019,127l/ 62 Czerwonka 210502 X FOREIGN PATENTS 1,130, 459 9/56 France.

REUBEN FRIEDMAN, Primary Examiner.

GEORGE D, MITCHELL, HERBERT L. MARTIN,

Examiners.

1. A DRY CLEANING SOLVENT FILTER FOR REMOVING PARTICULATE MATTER ANDTREATING A LIQUID DRY CLEANING SOLVENT AND COMPRISING A FILTER CONTAINERHAVING A CONTAINER ADAPTED TO RECEIVE SOLVENT RETURNING FROM A DRYCLEANING APPARATUS AND A CONTAINING OUTLET ADAPTED TO SUPPLY SAID DRYCLEANING APPARATUS WITH FILTERED AND TREATED SOLVENT, SAID CONTAINERHAVING AN OPENING AND A CONVER FOR CLOSING SAID OPENING, AND A FILTERCARTRIDGE INSERTIBLE THROUGH SAID OPENING, SAID CARTRIDGE INCLUDING ABOTTO PLATE HAVING A FILTER OUTLET PORT, A TOP PLATE EFFECTIVELYIMPERFORATE AND IN SPACED PARALLEL RELATIONSHIP TO SAID BOTTOM PLATE, APERFORATED CYLINDER PERPENDICULAR TO SAID PLATES AND EXTENDINTHEREBETWEEN WITH ONE END THEREOF IN COMMUNICATION WITH SAID FILTEROUTLET PORT AND A LONGITUDINALLY EXTENDING ACCORDION-PLATED ANNULUS OFFILTER PAPER SHEETING INTERPOSED IN SANDWICHED RELATIONSHIP BETWEEN SAIDPLATES, SAID ACCORDION-PLEATED ANNULUS HAVING A CREASED RADIALLY INNERFOLD ENGAGING SAID PERFORATED CYLINDER AND A CREASED RADIALLY OUTER FOLDEXTENDING SUBSTANTIALLY TO THE PERIPHERY OF SAID PLATES, SAID FOLDSFORMING A PARTITION HAVING AN